Are Branch Constraints the Capacities?
Yes and No:
A branch constraint is generally expressed in the following mathematical form:
where:
br : represent the branches involved in the constraint
FLOWbr : the power flow on branch br calculated by the model
factorbr : A multiplier applied to power flow on branch br in the constraint
Limit :The maximum allowable value for the left-hand side (LHS) of the inequality.
So, The LHS is the weighted sum of branch flows, and the RHS is the constraint limit.
If all factorbr values are equal to 1, then the constraint directly reflects the total flow, making it equivalent to a capacity constraint — so the answer is Yes.
However, if any factorbr is not equal to 1 (including negative values, which indicate reverse flow), then the constraint is more complex — so the answer is No.
So, if all the factorbr in the contrain equal to 1 , then it is a "Yes". Otherwise it is a "No". Note that the factor can be negative that indicate the flow on the branch is in reverse direction.
Important Notes:
- The LHS and RHS do not indicate the direction of power flow.
- To estimate the change in capacity usage due to a change in demand, sum the flows of the branches involved in the constraint. If a branch has a negative factor, multiply its flow by -1.
- You can find branch flow data in the file BranchResults_TP.csv.
Hope this helps
Tuong Nguyen
